When I was at UBC, many classes were still held in the leftover WWII army shacks, which had no ventilation. At that time, health and safety, never mind environmental aspects, were of little concern. One of my chemistry laboratory classes was held in one of these buildings. In those days, we were taught to mouth pipette, a practice which is now forbidden. I had to pipette chloroform, getting the liquid only part-way up, then feeling dizzy and having to rush outside to catch my breath!